The structural and functional condition of biofilms is presently studied and evaluated by use of experimental laboratory devices such as bioreactors as generally known in the art. Such bioreactors induce growth of biofilm therein on glass microscope slides from which the biofilm is collected on glass beads subject to aeration within a testing chamber for experimental evaluation purposes. However, various problems heretofore arose with respect to such use of bioreactors involving poor aeration during the biofilm growth process and difficulty in selective removal of microscope slides without disruption of biofilm growth on the slides and collection thereof on the glass beads.